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A label-free lead(II) ion sensor based on surface plasmon resonance and DNAzyme-gold nanoparticle conjugates.

Authors
  • Wu, Huanan1
  • Wang, Shuokang1
  • Li, Sam Fong Yau2
  • Bao, Qi1
  • Xu, Qiyong3
  • 1 Shenzhen Engineering Laboratory for Eco-Efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, Guangdong, China. , (China)
  • 2 Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore. , (Singapore)
  • 3 Shenzhen Engineering Laboratory for Eco-Efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, Guangdong, China. [email protected] , (China)
Type
Published Article
Journal
Analytical and Bioanalytical Chemistry
Publisher
Springer-Verlag
Publication Date
Nov 01, 2020
Volume
412
Issue
27
Pages
7525–7533
Identifiers
DOI: 10.1007/s00216-020-02887-z
PMID: 32829439
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Detection of lead(II) (Pb2+) ions in water is important for the protection of human health and environment. The growing demand for onsite detection still faces challenges for sensitive and easy-to-use methods. In this work, a novel surface plasmon resonance (SPR) biosensor based on GR-5 DNAzyme and gold nanoparticles (AuNPs) was developed. Thiolated DNAzyme was immobilized on the gold surface of the sensor chip followed by anchoring the substrate-functionalized AuNPs through the DNAzyme-substrate hybridization. The coupling between the localized surface plasmon (LSP) of AuNPs and the surface plasmon polaritons (SPP) on the gold sensor surface was used to improve the sensitivity. The substrate cleavage in the presence of Pb2+ ions was catalyzed by DNAzyme, leading to the removal of AuNPs and the diminished LSP-SPP coupling. The optimal detection limit was 80 pM for the sensor fabricated with 1 μM DNAzyme, corresponding to two or three orders of magnitude lower than the toxicity levels of Pb2+ in drinking water defined by WHO and USEPA. By tuning the surface coverage of DNAzyme, the sensitivity and dynamic range could be controlled. This sensor also featured high selectivity to Pb2+ ions and simple detection procedure. Successful detection of Pb2+ ions in groundwater indicates that this method has the prospect in the onsite detection of Pb2+ ions in water. Given the variety of AuNPs and metal-specific DNAzymes, this detection strategy would lead to the development of more sensitive and versatile heavy metal sensors. Graphical abstract.

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